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(No Model.)

J. K. MURPHY. EXTENSION BRAGB PoR EXGAVATIONS. Y.1\Io.`60.66 3.1.

Patented June 28, 1898.

y W/TNESSES BY ym AT HN UNITED STATES PATENT Orricne JAMES K. MURPHY, OF IVASIIINGTON, DISTRICT OF COLUMBIA. I

EXTENSION-BRACE.

FOR ExcAvATloNs.

srEcIFIcATIoN forming part of Lettere Patent Noteoeeei, dated June 2s, 189s.

To a/ZZ whom t may concern: v

Beit known that I, iJAMES K. MURPHY, a; citizen of the United States, residing at Washington city, in the District of Columbia, have invented certain new and useful Improvements in Extension-Braces for Excavations; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in extensible braces for supporting the walls of excavations, such as sewers, tunnels, &c'.

The objects of my invention are to provide a simple and secure, brace embodying oomparative lightness and great strength and also economy in the use of timber 3v and with. these ends in view myinvention consists in formi-ng the brace of parallel or camber timbers having at suitable predetermined localities pack-blocks intervening between the timbers and securely held in place, and the timbers secured by bolts passing through the timbers and pack-blocks and providing one end of the brace with any suitable shoe and the opposite end with a shoe and screw, all as will be hereinafter more fully set forth.

In order that those skilled in the art to which my invention appertains may know how to make and use the same, I will proceed to describe/the construction and method-of using the same, referringby letters to the aocompanying drawings, in which l Figure l is a perspective view of one of my improved braces. Fig. 2 is a similar view showing the timbers secured in such manner as to produce a double camber; and Fig. 3 is aview similar to Fig. 1, but showing the side timbers composed of two or more sections.

, Similar letters of reference denote like parts in the several figures of the drawings. A A represent two timbers, usually threeby twelve inches and of any length desired, according to the locality at which it is desired to use the same. The two timbers A A are separated by pack-blocks B, arranged at each end and at any suitable number of points intermediate of the end, as clearly shown. The timbers and pack-blocks are secured rigidly together by screw-bolts C and and at decreased cost of manufacture.

yimitation nea sept'etber 4,1897, serieiNe. 650,647. ure meter) -nuts D, withwashers E arranged, as shown, between the heads'of the bolts and one timber and between the securing-'nuts D and the other timber.

. One end of the brace is provided with a shoe F, having spurs G or corrugations at its sole and made in box form or with a socket to receive the end of the brace, to which it is rigidly secured bythe bolts, which also secure in place the end pack-blocks. posite end of the brace is provided with a casting II,which is secured in place in a similar manner to the shoe F by bolts passing through the casting, timbers, and end packblock. The end of the casting H is bored centrally to permit a screw I to freely traverse .through,-it, and theend pack-block is similarly bored'fr a like purpose.

J is a shoe connected by a ball or universal joint with outer end of the screw I, and K is a hand-nut travelingvpupon the thread of the screw I and adapted to bear against a suitable platform or collar surrounding the screwchannel in the casting H in order that the screw I, carrying the shoe J, may be extended outwardly or retracted by the rotation of the hand-nut for obvious purposes.

It will be seen that if the brace be made, as is customary, of solid timber it becomes necessary to bore the end to a depth suicient to accommodate the extreme inward movement of the screw, while according to my construction of double timbers and pack-blocks it is only necessary to bore through the pack-block, because the screw is free to move into the space between the timbers.

Another advantage of my improved construction rests in the fact that I am enabled to secure substantially the same strength that is provided by a solid brace, with less weight For instance, with two three by'twelve inch timbers and three-inch intervening pack-blocks I secure a brace having all the advantages of a solid brace nine by twelve inches and with a crushing resistance equal to a solid timber sixteen by sixteen inches. Still another advantage flows from the circumstance that by the employment of the pack-blocks intervening between the double timbers or stretchers the latter may be made in sections and from timber of less length than would be required |The op- IOO in the use of a solid brace. By reference to Fig. 3 it will be seen that the upper side of Ithe brace is composed of three sections and the lower side of two sections so arranged as to break joints and rigidly secured to packbloeks in such manner as to produce a continuous brace having substantially as much strength and stiffness as a solid brace. As lumber` of a given width and thickness increases in price accordingtoincrease in length, it will be readily seen that my improved coust-ruction involves great economy.

In the construction shown at Fig. l, wherein the side timbers are parallel, the packblocks are arranged flat; but when it is desired to produce a brace with a double calnber the paclbbloelis are arranged lengthwise and may be of any length, according to the camber desired.

It will be understood that the construction shown in the braces may be zulvantageously employed also in pack-posts for bridge-building.

That I claim as new, and desire to secure by Iietlers Iatent, is-

l.. An extensible brace for excavations comprising two wooden side beams separated by pack-blocks at each end and at points intermediate of the ends, said pack-blocks secured in position by bolts and nut-s as shown, a shoe F at one end and a casting II, screw I and nut K at the opposite end, substantially as and for the purpose set forth.

2. An excavation -brace comprising two wooden side beams A, A confined at one end by a metal shoe F and at the opposite end by a casting lI a screw I and nut K, pack-blocks between the ends of the side timbers, and intermediate pack-blocks B of greater length than the end blocks the blocks being secured by bolts and nuts, whereby a double cainber is produced, substantially as and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES K. MURPHY.

lVitnesses:

N. CUn'rrs LAnnoNn, Wn. C. Nehru-in. 

